First Report of Hematopoietic Stem Cell Transplantation for Children Diagnosed with Wiskott-Aldrich Syndrome in Vietnam

Awareness of inborn error immunity, such as Wiskott-Aldrich syndrome (WAS), is still lacking in Vietnam. The shortage of clinical immunologists and transplantation teams lead to poor prognosis for patients. Describe initial data about hematopoietic stem cell transplantation (HSCT) for WAS. Retrospective analyzing 15 procedures on 13 patients at the Vietnam National Children's Hospital from 2020 to 2024. The median age at HSCT was 34 months (range: 17-86). Of the patients, 73.3% received myeloablative conditioning based on busulfan, while 26.7% underwent reduced-intensity conditioning. Donor sources included matched sibling donors (MSD, 20.0%), unrelated cord blood (UCB, 33.3%), phenotypically identical family donor (MFD, 6.7%), and mismatched related donors (MMRD, 40.0%). The median stem cell dose was 4.9 × 10^6/kg of the recipient's body weight (range: 0.33 to 10.4 × 10^6/kg). Neutrophil and platelet engraftment occurred at a median of 14 days (range: 10-19) and 48 days (range: 14-143), respectively. By day +30, 73.3% of patients achieved full donor chimerism. One patient experienced graft failure, and another faced graft rejection two months post-transplant, both of whom underwent a second transplant with different donors. The overall survival rate was 92.3% with a median follow-up of 23 months (range: 6-53), with one patient died from chronic graft-versus-host disease (cGVHD). All surviving patients achieved normalization of platelet counts. HSCT offers significant benefits to WAS patients, achieving an excellent overall survival rate.